Stainless steel having passive fluoride film formed thereon and equipment manufactured therefrom

Abstract

A stainless steel with a passive state fluorinated film formed thereon, which is easy to construct and does not produce particles even when it is welded, and a device using the same. The stainless steel does not cause leakage even when said film is formed on a sealing surface of a joint and a valve seat surface. The stainless steel is characterized in that at least a part of the surface coated with a passive state fluorinated film not thicker than 190Å consisting of a metal fluoride as a main component.

What is claimed is:  
     
       1. A stainless steel material comprising stainless steel with a passive state fluorinated film formed thereon, said passive state fluorinated film having a metal fluoride as a main component and formed into a 190 Å thick or less layer on at least a part of the material surface, at least a surface part of said passive state fluorinated film being constituted of a layer of iron fluoride as a main component. 
     
     
       2. The stainless steel material according to  claim 1 , wherein said passive state fluorinated film is a film obtained by heating the material in a gaseous atmosphere containing fluorine to first form a metal fluoride film thereon and thereafter heat-treating the metal fluoride film in an inert gas. 
     
     
       3. A device, comprising: 
       a first steel component made of the stainless steel material according to  claim 1 ; and  
       a second welding component welded to said first steel component.  
     
     
       4. The device according to  claim 3 , wherein said device is one of a device for gas storage, a device for gas supply, and a device for gas reaction. 
     
     
       5. The device according to  claim 3 , wherein said device is one of a gas cylinder, a gas piping, a reducing valve, a filter, a flow meter, a pressure gauge, a mass-flow controller, a valve, a check valve, a joint, an RIE reaction system and a CVD reaction system, said device being configured for handling corrosive gasses. 
     
     
       6. The device according to  claim 3 , wherein said device is an excimer laser oscillator. 
     
     
       7. A device comprising a part made of stainless steel having the surface of the stainless steel according to  claim 1 , the surface of the stainless steel being used as a sealing surface for shutting off gas from the outside.